Encyclopedia of Chromatography Third Edition 1, 950-953 (2009). The author describes the standard guides of the ASTM designations for forensic writing ink comparison and identification using TLC. Recent advances such as software for visual comparison of chromatograms are included. In addition, new applications of TLC in the field of forensic ink analysis and comparison with spectrometric and chromatographic methods are also described.

International Journal of PharmaTech Research 03, 527-538 (2009). A stability indicating HPTLC method has been developed for analysis of cephalexin in bulk and dosage formulation. HPTLC on silica gel with ethyl acetate - methanol - 25 % ammonia 6:4:1. The hRf value was 56. Densitometric quantification at 260 nm. The method was linear in range of 500-1500 ng/band. Cephalexin was subjected to forced degradation (acid, alkali, oxidation, thermal, photolytic). All degradation products were well separated from the drug, indicating specificity of the method.

J Young Pharm 1(3), 259-263 (2009). A validated HPTLC method is described for simultaneous estimation of amlodipine besylate and telmisartan in dosage form. HPTLC on silica gel with tetrahydrofuran - dichloroethane - methanol - 25 % ammonia solution 60:20:10:4. The hRf value of amlodipine besylate was 45 and of telmisartan 22. Densitometric evaluation at 326 nm. Linearity was in the range of 1200-7200 ng/band for telmisartan and 400-1400 ng/band for amlodipine besylate. The limit of detection was 149 ng/zone and 53 ng/zone for telmisartan and amlodipine besylate, respectively. The limit of quantification was 453 ng/zone for telmisartan and 161 ng/zone for amlodipine besylate. The recovery was between 100.4 and 100.8 %.

fruits rind by using high-performance thin-layer chromatography. Asian Journal of Chemistry 23(2), 788-790 (2011). A simple HPTLC method has been developed for estimation of beta-carotene in fruit rind of Diplocyclos palmatus (Cucurbitaceae). The rind of fruits was extract with acetone. HPTLC on silica gel with petroleum ether as mobile phase. The hRf value of beta-carotene was 30. Densitometric evaluation at 450 nm. The method was linear in the range of 6-60 ng/band. The recovery was 99.4 % for beta-carotene.

J. Planar Chromatogr. 23, 282-285 (2010). HPTLC of compactin and citrinin on silica gel with toluene - ethyl acetate - formic acid 3:2:1 in a twin-trough chamber saturated for 30 min at room temperature and a relative humidity of 60 +/- 5 %. Quantitative determination by absorbance measurement at 238 nm and 366 nm. The hRf of compactin and citrinin was 47 and 62, respectively. Good correlation was obtained between peak area and concentration, with a determination coefficient r2= 0.998 for compactin and 0.996 for citrinin.

J. Planar Chromatogr. 23, 286-288 (2010). TLC of taxol with a stationary-phase gradient whereby parts of different TLC plates were connected by use of a MIGAS device. Separated taxol-containing zones were developed with methanol over 1 cm and thus moved to another plate. The lipophilic substance zone was cut out after separation of the sample on a silica gel plate with n-heptane - ethyl acetate 1:1. Further separation of taxol from accompanying hydrophilic substances was carried out on HPTLC RP-18W with methanol - water 4:1. The taxol-containing fraction was finally separated on silica gel with chloroform - acetone 3:1 in a horizontal chamber at constant temperature (30 +/- 1°C) and humidity (35 +/- 1 %). Detection under UV 254 and 366 nm. Quantitative determination by densitometry at 220 nm. The precision (n = 7) was 0.63 % and the repeatability (n = 7) 3.35 %. The limit of detection and quantification was 0.50 and 1.00 µg/zone, respectively; the correlation coefficient from linear regression was >0.98, and the linear calibration range was 1 - 10 µg/zone.

J. Planar Chromatogr. 23, 339-342 (2010). HPTLC of saccharin in foodstuffs (e. g. cola drinks, lemon juices, betel nut powder, mouth fresheners, ice candy, and tabletop sweeteners) on silica gel with chloroform - methanol - acetic acid 64:35:1 or acetone - isopropanol - acetic acid 60:39:1. Quantitative determination by absorbance measurement at 230 nm. Linearity was between 250 - 1250 ng/µL. The limit of detection and quantification for saccharin were 40 and 130 ng, respectively. Mean recovery from spiked samples was 102.3 % for cola drinks and 98.8 % for lemon juices. Relative standard deviation (% RSD) for cola drinks, lemon juices, ice candy, mouth freshener, betel nut powders, and tabletop sweeteners were 2.1, 4.2, 3.4, 3.0, 4.9, and 4.1 %, respectively.

J. Chromatogr. A 1218 (19), 2692-2699 (2011). HPTLC coupled with bioluminescence detection can be used for screening for unknown substances. So far the HPTLC plate was dipped in an aqueous solution of Vibrio fischeri bacteria. However polar substances may be dissolved during this process, which leads to blurring and tailing of the zones on the plate. This was overcome by application of the bacteria solution by rolling. A rolling device was made of commercially available household articles and tested using octhilinone and methylparaben. Comparison of rolling with dipping showed that despite the manual steps involved in the rolling process, the results were reproducible. Depending on the substance and its amount on the HPTLC plate, with rolling peaks were narrower, up to a factor of 4 higher and showed a higher signal-to-noise ratio than with dipping.